Coating-free ocean atmospheric corrosion resisting high-strength bolt steel for bridge structure and manufacturing method

Abstract

The invention discloses ocean atmospheric corrosion resisting high-strength bolt steel for a coating-free bridge structure and a manufacturing method, and belongs to the technical field of steel for bridge structure connection. The steel is prepared from, by weight, 0.16%-0.45% of C, 0.01%-2.2% of Si, 0.3%-2.5% of Mn, 0.001%-0.024% of P, 0.002%-0.025% of S, 0.0005%-0.0100% of B, 0.01%-0.50% of Ti, 0.01%-0.20% of V, 0.001%-0.15% of Al, 0.35%-3.2% of Cr, 0.2%-0.6% of Cu, 0.2%-2.5% of Ni and the balance Fe and trace impurities. The corrosion resisting index I, calculated according to a chemical ingredient prediction formula, of the high-strength weather-proof bolt steel is larger than or equal to 6.3, the properly produced bolt specification range is M16-30 mm, after the bolt steel is beaten into bolts through a bolt machining factory, oil hardening of 840 DEG C to 920 DEG C and tempering of 380 DEG C to 625 DEG C are included in a quenched-tempered heat treatment system, and optimum high toughness matching is obtained. The bolt steel has the beneficial effects that the 10.9-grade high-strength bolts are used for matching connection of coating-free bridge structure plates and profiles, and have excellent ocean atmospheric corrosion and low temperature resisting performance.

Description

technical field [0001] The invention belongs to the technical field of steel for bridge structure connection, and in particular relates to a 10.9-grade paint-free bridge structure with marine atmospheric corrosion-resistant high-strength bolt steel and a manufacturing method, which is suitable for the processing and manufacture of bolt specifications M16-30mm weather-resistant high-strength bolts. Background technique [0002] Due to the advantages of high strength, light weight, low foundation cost, short construction period, ability to solve complex problems in large spaces, and good earthquake resistance, steel structures have rapidly developed under the government's encouraging policies. Steel structures are used in various atmospheric environments, and corrosion is a natural phenomenon. All domestic steel structure bridges are anti-corrosion by coating method, and the high-strength bolts used for connection are coated with the bridge as a whole. However, methods such a...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a kind of 10.9-class high-strength bolt steel for paint-free bridge structures and its manufacturing method, which solves the problem that ordinary 10.9-class high-strength bolts are not resistant to atmospheric environment corrosion, but the surface spraying needs to be anti-corrosion every 3 to 5 years Coating maintenance and re-corrosion coating every 10 to 15 years, and the coating process causes health hazards, environmental pollution, high coating costs, etc.

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